When an electrical installation is subject to fluctuating loads or an increase in capacitive power, traditional capacitor banks often fall short. A Static Var Generator (SVG) offers the most precise solution in such cases. By compensating for reactive power electronically, at lightning speed and continuously, you improve operational reliability and prevent unnecessary overloading of the installation.
Short on time? Here are the key points you need to know about the Static Var Generator:
What is it? An electronic, active compensator that reacts at lightning speed to fluctuations in reactive power (both inductive and capacitive).
Why is this important? It prevents energy losses, reduces thermal stress on cables and transformers, and ensures stable power quality without the risk of resonance.
How to recognise the need? High penalties for blind consumption on energy bills, unexplained failures of protective devices, or overheated components when machinery is changing.
What can you do? Proactively analyse the installation using measurements to determine whether an SVG or a conventional capacitor bank is the right technical solution.
Switching to or implementing a Static Var Generator is a strategic choice for operational reliability. This technology is specifically relevant to:
A Static Var Generator (SVG) is an advanced system for the electronic compensation of reactive power. Whereas conventional capacitor banks switch in fixed, often slow steps using passive components, an SVG utilises power electronics. This enables reactive power to be compensated continuously, dynamically and within a few milliseconds.
In many industrial installations, the load varies continuously. A conventional capacitor bank operates in fixed steps. This means that the installation is almost always over- or under-compensated. An SVG, on the other hand, analyses the demand in real time and supplies exactly the right amount of reactive power. This results in a perfectly stable power factor. Furthermore, unlike a capacitor bank, an SVG can also compensate for capacitive networks.
Note: An SVG is often referred to as ‘active compensation’. Do not confuse this directly with an Active Harmonic Filter (AHF). An SVG is primarily designed for reactive power and is highly robust against harmonic voltage, but does not independently remove harmonic current from the installation. An AHF is required for that.
A poor ratio between active and reactive power (a low power factor) poses a direct threat to operational reliability. As installations become more modern, the nature of the load changes. The importance of a power factor corrector (PFC) is evident in several areas:
Ensuring continuity: An SVG responds within a few milliseconds. This allows the reactive inrush currents from large motors to be supplied immediately, which drastically reduces the risk of catastrophic voltage dips and the failure of sensitive equipment.
System lifespan: Reactive current is current that flows through the cables but does not perform any useful work. This causes additional heating in cables and transformers. By compensating for this at source, you reduce the thermal load and prevent accelerated ageing of components.
Financial security: As well as preventing ‘Reactive Power Transmission Charges’ on the grid operator’s bill, these efficiency improvements lead to reduced energy losses and thus a direct reduction in CO₂ emissions.
No risk of impedance: This is perhaps the most important technical argument in favour of an SVG. A conventional capacitor bank is extremely sensitive to harmonic voltage. As the graph below shows, the impedance (resistance) of a capacitor decreases as the frequency in the grid increases. As a result, the capacitor bank attracts unwanted, high-frequency harmonic currents, leading to overheating and a real risk of dangerous resonance.
Power quality issues often creep into an installation unnoticed following modifications or extensions. You can recognise the need for advanced compensation by the following symptoms:
Take, for example, a large office building that recently replaced its entire lighting system with sustainable LED lighting whilst simultaneously significantly expanding its IT equipment. Shortly after this modernisation programme, the existing, relay-switched capacitor bank repeatedly failed, posing an immediate risk to business continuity.
Through a proactive approach and a measurement using a Power Quality Analyser, the situation was accurately assessed. The analysis revealed that the power demand had become highly capacitive due to the large amount of new electronic equipment, combined with increased harmonic voltage. The traditional capacitor bank was not designed for this, could not cope with the situation and even created a dangerous risk of resonance.
The final solution involved replacing the outdated capacitor bank with a Static Var Generator. From that point onwards, the capacitive reactive power was continuously and accurately compensated. The risk of resonance was structurally resolved and the overall operational reliability of the installation was once again guaranteed for the long term.
The structure of industrial and commercial plants has changed dramatically over the past decade. Previously, linear and inductive loads, such as direct-on-line motors and heavy transformers, dominated. For these, a conventional fixed-stage capacitor bank was an adequate and cost-effective solution.
Today, three developments are causing new challenges:
Improving your Power Quality and increasing the power factor requires a proactive approach. Depending on the dynamics in your installation, there are hardware and structural solutions.
When do you choose a conventional capacitor bank?
If your installation consists of stable, continuous inductive loads (e.g. large pumping stations running 24/7) without significant harmonic contamination. This is often a robust and highly cost-effective method, if correctly designed and fitted with the right tuning (coils) to dampen wear due to small harmonic voltages.
When is a Static Var Generator the only right choice?
Note: In some cases, an SVG may appear to be oversized for a simple application. A thorough diagnosis prior to investment prevents unnecessary capital expenditure and ensures that you receive the technology your installation actually requires.
Follow these steps for a proactive approach and ensuring operational reliability:
While reading a penalty on the energy bill is easy, correctly sizing electronic compensation is work for specialists. You need specific metering data and in-depth network knowledge. Call in expertise when:
Delve further into the subject matter via these related pages:
Symptoms are often subtle until things go wrong. Look out for unexplained machine failures, flickering lights, cables getting hot or transformers buzzing. Also, if electronics (PLCs, drivers) fail earlier than the service life indicates, chances are that the power quality is insufficient. A Power Quality measurement provides the answer.
This is possible, provided you have a high-quality Power Quality Analyzer (according to IEC 61000-4-30 Class A) and the knowledge to interpret the data. Collecting data is easy; analysing the correlation between events, harmonics and your specific business processes requires specialist engineering knowledge. We are happy to support you in the analysis.
Not by definition. NEN-EN 50160 describes the minimum requirements for voltage at the grid operator's transfer point. However, modern equipment can be more sensitive and malfunction even if the voltage is within this standard. We therefore look beyond the standard: we look at the compatibility between your power supply and your connected load.
Peace of mind, certainty and insight. You get a clear diagnosis of the 'health' of your electrical installation. We pinpoint the cause of faults, enabling you to avoid unplanned downtime and reduce fire risks or unnecessary energy losses. You receive a concrete advisory report with practical points for improvement.
No, that is a misconception. A filter is a powerful tool, but not a panacea. Sometimes the solution lies in changing transformer settings, redistributing loads or adjusting cabling. HyTEPS always recommends a thorough analysis and simulation before we recommend hardware, to avoid unnecessary investments.
Yes, significantly. Solar panel inverters and LED lighting drivers are non-linear loads that cause harmonics and sometimes supraharmonics. This can lead to interference with other equipment or overloading of the neutral conductor. When renovating or preserving, a Power Quality check is essential to ensure operational reliability.
We call this phenomenon 'nuisance tripping'. Often the cause is not the total amount of current, but the distortion of the current (harmonics) or short peak currents that your measuring equipment misses. This contamination can extra heat up thermal protections or confuse electronic protections, causing them to switch off wrongly. A specialised measurement can find out exactly why a protection reacts.
For a reliable picture, we usually measure at least one to two weeks. This is necessary to capture a full duty cycle, including weekends and peak loads. For specific acute failures, we can also take short-term measurements or deploy 'continuous waveform recording' to capture transients.
Your installer is an expert in installation and maintenance (the 'general practitioner'). HyTEPS is the specialist (the 'Power Quality Doctor'). We have advanced measuring equipment, simulation software and in-depth knowledge of theoretical electrical engineering and regulations. We often work together with installers to solve complex puzzles that fall outside standard knowledge.
After the measurement, you receive a report with conclusions in understandable language as well as technical details. If necessary, we simulate the possible solutions in our software. So you know exactly what the effect of a measure will be in advance. We then supervise the implementation and verify the result with a follow-up measurement.
Do not hesitate in case of unexplained failures. Speak to a HyTEPS engineer about your situation or request a Power Quality survey. We will help you find the cause and restore operational reliability.
HyTEPS
Beemdstraat 3
5653 MA Eindhoven
